Various types of medical electrical leads for use in cardiac rhythm management (CRM) and neurostimulation applications are known. In CRM applications, for example, such leads are frequently delivered intravascularly to an implantation location on or within a patient's heart, typically under the aid of fluoroscopy. Once implanted, the lead is coupled to a pulse generator or other implantable device for sensing cardiac electrical activity, delivering therapeutic stimuli, and/or for performing some other desired function within the body. Such leads often include one or more electrodes for sensing and delivering electrical stimuli and a proximal, terminal end which is connected to the pulse generator. The terminal end of the lead includes one or more electrical contacts that are electrically connected to the electrodes on the terminal end of the lead via a number of conductors.
In certain applications, the leads are tested for proper positioning and function as part of the implantation process and prior to being connected to the pulse generator, allowing the implanting physician to evaluate pacing and sensing performance prior to concluding that the particular lead position is suitable. During the testing process, for example, a Pacing System Analyzer (PSA) may be connected to the terminal end of the lead to test the connection of the conductor end of the lead to the heart and/or to evaluate the performance of the lead. To facilitate connection of the PSA to the lead, a lead implant tool can be temporarily coupled to the terminal end of the lead, allowing the conductors of the PSA to be connected to the electrical contacts on the terminal end of the lead.
More recent trends in lead designs have focused on the development of lead connectors with up to four electrical contacts. The terminal ends of such leads are not significantly different in size from previous, IS-1 standard leads, which include only two terminal contacts. Many existing spring-loaded clips used for connecting the PSA to the terminal contacts are often inadequate for use with more modern lead designs, particularly due to the limited spacing between the contacts, and since the space between the contacts is sometimes used as a sealing area to ensure electrical isolation.